The Rio Itapecuru is a major river in Maranhão state, northern Brazil, stretching approximately 1,041 kilometers from its headwaters in the Serra da Crueira in the south to its mouth at Baía do Arraial, an arm of the larger Baía de São José southeast of the Ilha do Maranhão. The river flows in a broadly south-to-north direction and carries an average discharge of around 470 cubic meters per second. Its width ranges between 50 and 120 meters along much of its course, giving it a substantial channel suited to open-water paddling rather than technical whitewater.

The river drains a basin of roughly 53,000 square kilometers and serves as a critical freshwater source for some twenty municipalities, including São Luís. The headwaters are partially protected within the Mirador State Park, a 437,000-hectare reserve established in 1980. The lower reaches pass through transitional forest containing elements of both Amazonian flora and cerrado (savannah-like) vegetation, which shapes the riparian landscape paddlers would encounter in that section.

Historically, the Itapecuru was central to Maranhão's colonial economy, particularly cotton cultivation, and towns such as Caxias and Itapecuru-Mirim developed along its banks as commercial centers. This historical presence means the river corridor passes through or near several established settlements, which may offer logistical support for multi-day trips.

Formal access points, documented hazards, and regulated put-in or take-out locations vary along the river. Paddlers planning a trip should consult local outfitters or Brazilian waterway authorities, and note that recreational vessels operating in Brazilian waters require a Vessel Inscription Title (TIE/TIEM) issued through the Brazilian Navy's Directorate of Ports and Coasts.